1. Field of the Invention
The present invention relates to a throttle control device equipped with a throttle valve for controlling a flow rate of a fluid, and more specifically to a motor drive throttle control device for controlling the flow rate of air, for example, intake air to be supplied to an automotive engine. The present invention also relates to a method of mounting a motor to a throttle body of a throttle control device.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. 2001-132495 discloses a conventional throttle control device. In the throttle control device disclosed in this gazette, a throttle valve arranged in an intake passage formed in a throttle body is rotated by a motor. As the throttle valve rotates, the intake passage is incrementally opened and closed to thereby control the intake air amount. One end portion of the motor casing of the motor is fixed to the throttle body in a cantilever-like fashion, whereas the other end portion of the motor casing is spaced apart from the throttle body, i.e., in a so-called free state, with a predetermined gap being provided therebetween (Refer to pages 3 and 4 and FIG. 1 of the publication).
Japanese Laid Open Patent Publication No. 11-187604 discloses a throttle control device in which one end portion of the motor casing of the motor is fixed to the throttle body in a cantilever-like fashion, and the other end portion of the motor casing is supported by the throttle body via a resilient motor support member (Refer to pages 4 and 5 and FIG. 2 of the publication).
In the device as disclosed in Japanese Laid-Open Patent Publication No. 2001-132495, in which the other end portion of the motor casing is in a free state, this other end portion may vibrate in the radial direction of the motor casing due to various reasons, such as engine vibrations, road irregularities, etc. Thus, the device is limited in terms of the vibration resistance of the motor.
While the device as disclosed in Japanese Laid-Open Patent Publication No. 11-187604 has an improved vibration resistance of the motor as compared to Publication No. 2001-132495, it utilizes a rather complicated configuration in which the motor support member is fitted in its entirety into the other end portion of the motor casing. This complicated configuration results in a relatively high cost.